Squiz/ValidClassName: improve enum tests + bugfix

Ensure that backed enum signatures are included in the tests.

As this sniff retrieves the class name itself instead of using the `File::getDeclarationName()` method, these tests _will_ find the name correctly (not mistake the type for the name), but _may_ include the colon in the name as the "name end" determination checks on scope opener and whitespace and doesn't take the colon for the type declaration into account.

Author: jrfnl

src/Standards/Squiz/Sniffs/Classes/ValidClassNameSniff.php

@@ -59,7 +59,7 @@ public function process(File $phpcsFile, $stackPtr)
         // starting with the number will be multiple tokens.
         $opener    = $tokens[$stackPtr]['scope_opener'];
         $nameStart = $phpcsFile->findNext(T_WHITESPACE, ($stackPtr + 1), $opener, true);
-        $nameEnd   = $phpcsFile->findNext(T_WHITESPACE, $nameStart, $opener);
+        $nameEnd   = $phpcsFile->findNext([T_WHITESPACE, T_COLON], $nameStart, $opener);
         if ($nameEnd === false) {
             $name = $tokens[$nameStart]['content'];
         } else {

src/Standards/Squiz/Tests/Classes/ValidClassNameUnitTest.inc

@@ -138,7 +138,7 @@ trait Base
 }
 
 // Valid enum name.
-enum ValidCamelCaseClass {}
+enum ValidCamelCaseClass: string {}
 
 
 // Incorrect usage of camel case.
@@ -147,22 +147,22 @@ enum Invalid_Camel_Case_Class_With_Underscores {}
 
 
 // All lowercase.
-enum invalidlowercaseclass {}
+enum invalidlowercaseclass: INT {}
 enum invalid_lowercase_class_with_underscores {}
 
 
 // All uppercase.
-enum VALIDUPPERCASECLASS {}
+enum VALIDUPPERCASECLASS: int {}
 enum INVALID_UPPERCASE_CLASS_WITH_UNDERSCORES {}
 
 
 // Mix camel case with uppercase.
-enum ValidCamelCaseClassWithUPPERCASE {}
+enum ValidCamelCaseClassWithUPPERCASE : string {}
 
 
 // Usage of numeric characters.
 enum ValidCamelCaseClassWith1Number {}
-enum ValidCamelCaseClassWith12345Numbers {}
+enum ValidCamelCaseClassWith12345Numbers : string {}
 enum ValidCamelCaseClassEndingWithNumber5 {}
 
 enum Testing{}